The North American species of Psathyrella.

1972]

PSATHYRELLA

189

fertae, latae, dilute cacaocolor, demum fumoso-cacaocolor; stipes 4-6 cm longus,
3-4 mm crassus, connatus, albidus deorsum demum brunneus; sporae 8-11X
5-6.2 p/; pleurocystidia 40-55x12-18 1u, pedicellato-ventricosa, ad apicerum
rotundata; fibulae adsunt. Typus. Smith 71791 (MICH); legit prope Cross
Village, Michigan.
Illust. P1. 36, fig. a; Text Figs. 326-329.
Pileus 1-3 cm broad, obtusely conic with a straight margin, becoming
expanded-umbonate, surface at first with a thin white coating of outer veil fibrils,
the margin appendiculate at first for a short time, soon glabrescent over all, color
a pale cinnamon-brown when young and moist, hygrophanous and fading in
streaks on the margin first and often appearing pallid-rimose. Context thin and
fragile, pale dingy buff, odor and taste not distinctive-the odor somewhat earthypungent, with FeSO4 no reaction.
Lamellae close, moderately broad, depressed-adnate, seceding, pallid cocoabrown when young, near "warm sepia" (dark reddish brown) in age, edges even.
Stipe 4-6 cm long, 3-4 mm thick, equal or tapered to a pointed base-causing
the cluster to be connate-whitish at first, base finally brownish from handling,
arising from a firm basal mycelial mass (oozonium-like), no pseudorhiza present.
Veil white, leaving a zone when it breaks and surface of stipe below this line
coated thinly with fibrils but soon glabrous.
Spores dark chocolate-color in deposit, 8-11 x5-6.2 /A, smooth but in KOH
appearing slightly mottled, apex truncate from a broad pore, shape in face view
ovate to elliptic, in profile obscurely inequilateral, color in KOH dark brown with
a cocoa tinge, slowly changing to dark chocolate-brown, bay-brown in Melzer's
wall about 0.5, thick.
Basidia 4-spored, 18-23x8-10 ~/, hyaline, short and broad. Pleurocystidia
40-55 x 12-18 A, pedicellate-ventricose and tapered slightly to a broadly rounded
apex, smooth, thin-walled, hyaline, content not distinctive in either KOH or
Melzer's. Cheilocystidia shorter and more ovate-pedicellate but otherwise as for
the pleurocystidia. Caulocystidia mostly vesiculose to clavate but some elongated
and with a medial broad constriction, hyaline, smooth, the content not distinctive.
Pileus cuticle a layer of vesiculose cells about 2 deep, the walls hyaline or
ochraceous in KOH and both smooth and thin; subcuticular region and tramal
hyphae ochraceous to clay color revived in KOH, walls smooth. Clamps present.
No distinctive reactions on any tissue when mounted in Melzer's.
Type locality. Wycamp Lake, Emmet County, Michigan.
Habit and habitat. Cespitose on humus in an alder-aspen slashing, July.
Distribution. Emmet County, Michigan.
Observations. The distinctive features of this species include the mycelial mat
around the clusters of basidiocarps, the wide spores for their length, the wide and
rounded pleurocystidia, the large vesiculose caulocystidia along with the other
types as described, the outer veil, and habit of fruiting in clusters. Drosophila
pannucioides (Lange) Kihn. & Romagn. has spores 7.5-9.5 x 5-5.7 /[ but the outer
veil is heavy and relatively persistent.
Material examined. Michigan: Smith 71790, 71791 (Type).
147. Psathyrella vialis A. H. Smith, sp. nov.
Pileus 1-3.5 cm latus, obtuse conicus vel convexus, demum late campanulatus
vel subplanus, sparse griseo-fibrillosus, glabrescens, badius vel subferrugineus,
demum spadiceus; lamellae sordide cinnamomeae demum subhepaticolor; stipes